Dielectric spectroscopy of conductive polyaniline salt films

Dielectric responses of polyaniline (PANI) salt films, made from two different methods, were compared to investigate the effect of a dopant and film‐formation methods on the dielectric properties. One of the film‐formation methods for emeraldine salt was the film‐doping method, and the other, the solution‐doping method. The conductivity relaxation and dielectric properties were measured by a microdielectrometer at 293 K in the frequency range of 1–100,000 Hz. Dielectric spectra were a function of the dopant in the case of the film‐doping method, whereas it was a function of solvent–dopant combinations as well as the dopants in the solution‐doping method. The dielectric responses of film‐doped samples had similar patterns irrespective of the dopants, while those of solution‐doped samples were varied, probably due to different conjugation conditions or/and the conduction mechanism. In the case of film‐doped samples, dielectric loss and permittivity values were increased with decreasing dopant sizes. The dielectric relaxation times were also varied depending on the kind of dopants. The different solvent–dopant combinations led to variation of the dielectric responses in the solution‐doped PANI due to an altered chain structure. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2760–2769, 2001